Druid extensions

Druid implements an extension system that allows for adding functionality at runtime. Extensions
are commonly used to add support for deep storages (like HDFS and S3), metadata stores (like MySQL
and PostgreSQL), new aggregators, new input formats, and so on.

Production clusters will generally use at least two extensions; one for deep storage and one for a
metadata store. Many clusters will also use additional extensions.

Community Extensions

Community extensions are not maintained by Druid committers, although we accept patches from community members using these extensions. They may not have been as extensively tested as the core extensions.

A number of community members have contributed their own extensions to Druid that are not packaged with the default Druid tarball.
If you'd like to take on maintenance for a community extension, please post on dev@druid.apache.org to let us know!

All of these community extensions can be downloaded using pull-deps with the coordinate org.apache.druid.extensions.contrib:EXTENSION_NAME:LATEST_DRUID_STABLE_VERSION.

Promoting Community Extension to Core Extension

Please post on dev@druid.apache.org if you'd like an extension to be promoted to core.
If we see a community extension actively supported by the community, we can promote it to core based on community feedback.